Striatal magnetic resonance spectroscopy abnormalities in young adult SAPAP3 knockout mice

BACKGROUND

Obsessive compulsive disorder (OCD) is a debilitating condition with lifetime prevalence of 1-3%. OCD typically arises in youth but delays in diagnosis impede optimal treatment and developmental studies of the disorder. Research using genetically modified rodents may provide models of etiology that enable earlier detection and intervention. The SAPAP3 knockout (KO) transgenic mouse was developed as an animal model of OCD and related disorders (OCRD). KO mice exhibit compulsive self-grooming behavior analogous to behaviors found in people with OCRD. Striatal hyperactivity has been reported in these mice and in humans with OCD.

METHODS

Striatal and medial frontal cortex 9.4 Tesla proton spectra were acquired from young adult SAPAP3 KO and wild-type control mice to determine whether KO mice have metabolic and neurochemical abnormalities.

RESULTS

Young adult KO mice had lower striatal lactate (P=0.006) and glutathione (P=0.039) levels. Among all mice, striatal lactate and glutathione levels were associated (R=0.73, P=0.007). We found no group differences in medial frontal cortex metabolites. At the age range studied, only 1 of 8 KO mice had skin lesions indicative of severe compulsive grooming.

CONCLUSION

Young adult SAPAP3 KO mice have striatal but not medial frontal cortex MRS abnormalities that may reflect striatal hypermetabolism accompanied by oxidative stress. These abnormalities typically preceded the onset of severe compulsive grooming. Our findings are consistent with striatal hypermetabolism in OCD. Together, these results suggest that striatal MRS measures of lactate or glutathione might be useful biomarkers for early detection of risk for developing compulsive behavior disorders.

Mice with Shank3 Mutations Associated with ASD and Schizophrenia Display Both Shared and Distinct Defects

Genetic studies have revealed significant overlaps of risk genes among psychiatric disorders. However, it is not clear how different mutations of the same gene contribute to different disorders. We characterized two lines of mutant mice with Shank3 mutations linked to ASD and schizophrenia. We found both shared and distinct synaptic and behavioral phenotypes. Mice with the ASD-linked InsG3680 mutation manifest striatal synaptic transmission defects before weaning age and impaired juvenile social interaction, coinciding with the early onset of ASD symptoms. On the other hand, adult mice carrying the schizophrenia-linked R1117X mutation show profound synaptic defects in prefrontal cortex and social dominance behavior. Furthermore, we found differential Shank3 mRNA stability and SHANK1/2 upregulation in these two lines. These data demonstrate that different alleles of the same gene may have distinct phenotypes at molecular, synaptic, and circuit levels in mice, which may inform exploration of these relationships in human patients.

Modeling psychiatric disorders for developing effective treatments

Recent advances in identifying risk-associated genes have provided unprecedented opportunities for developing animal models for psychiatric disease research with the goal of attaining translational utility to ultimately develop novel treatments. However, at this early stage, successful translation has yet to be achieved. Here we review recent advances in modeling psychiatric disease, discuss the utility and limitations of animal models, and emphasize the importance of shifting from behavioral analysis to identifying neurophysiological abnormalities, which are likely to be more conserved across species and thus may increase translatability. Looking forward, we envision that preclinical research will align with clinical research to build a common framework of comparable neurobiological abnormalities and to help form subgroups of patients on the basis of similar pathophysiology. Experimental neuroscience can then use animal models to discover mechanisms underlying distinct abnormalities and develop strategies for effective treatments.

Bacterial attachment and biofilm formation on surfaces are reduced by small-diameter nanoscale pores: how small is small enough?

BACKGROUND/OBJECTIVES

Prevention of biofilm formation by bacteria is of critical importance to areas that directly affect human health and life including medicine, dentistry, food processing and water treatment. This work showcases an effective and affordable solution for reducing attachment and biofilm formation by several pathogenic bacteria commonly associated with foodborne illnesses and medical infections.

METHODS

Our approach exploits anodisation to create alumina surfaces with cylindrical nanopores with diameters ranging from 15 to 100 nm, perpendicular to the surface. The anodic surfaces were evaluated for attachment by Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus epidermidis. Cell-surface interaction forces were calculated and related to attachment.

RESULTS

We found that anodic alumina surfaces with pore diameters of 15 and 25 nm were able to effectively minimise bacterial attachment or biofilm formation by all the microorganisms tested. Using a predictive physicochemical approach on the basis of the extended Derjaguin and Landau, Verwey and Overbeek (XDLVO) theory, we attributed the observed effects largely to the repulsive forces, primarily electrostatic and acid-base forces, which were greatly enhanced by the large surface area originating from the high density, small-diameter pores. We also demonstrate how this predictive approach could be used to optimise different elements of surface topography, particularly pore diameter and density, for further enhancing the observed bacteria-repelling effects.

CONCLUSIONS

We demonstrate that anodic nanoporous surfaces can effectively reduce bacterial attachment. These findings are expected to have immediate, far-reaching implications and commercial applications, primarily in health care and the food industry.

Determination of the potential of induced pluripotent stem cells to differentiate into mouse nucleus pulposus cells in vitro

We determined the potential for induced pluripotent stem (iPS) cells to differentiate into nucleus pulposus (NP)-like cells in mice. iPS cells were generated from tail-tip fibroblasts. We used a pellet culture model with the aim of determining the applicability of iPS cell-based therapy to intervertebral disc degeneration (IVD). The cell pellet was cultured in an NP cell basal medium comprising Dulbecco's modified Eagle's medium supplemented with transforming growth factor beta 1, dexamethasone, ascorbate-2-phosphate, and 1% ITS-Premix. The pellet was evaluated by quantitative reverse transcription polymerase chain reaction, immunohistochemical staining, and biochemical composition. The differentiation of iPS cells into NP cells was demonstrated by the protein and mRNA expression levels of proteoglycan, collagen II, aggrecan, and CD24. Furthermore, increased hydroxyproline content and dimethylmethylene blue staining demonstrated that the collagen II and glycosaminoglycan content in the NP cells increased with time. We have shown that cultured mouse iPS cells can be induced to differentiate into NP cells. Such proof-of-concept opens up the possibility of producing patient-specific NP cells in a relatively simple and straightforward manner with high efficiency. We are confident that such cells could be immediately useful for the study of IVD disease.

Modification of artificial sea water for the mass production of (+)-terrein by Aspergillus terreus strain PF26 derived from marine sponge Phakellia fusca

(+)-Terrein shows multiple bioactivities, however, its mass production is a big challenge. Aspergillus terreus strain PF26 derived from South China Sea sponge Phakellia fusca has been cultured to produce (+)-terrein successfully, but artificial sea water (ASW) of high salinity used in the fermentation medium may cause the corrosion risk of metal bioreactor, which limits the fermentation on a large scale. In this study, we modified the components of ASW by removing NaCl and CaCl2 from the original formula, which reduced about 80% salinity of ASW. As a result, 7·56 g l(-1) (+)-terrein production was achieved in shake flask, which was 78·72% higher than using the original ASW, and the cultivation time was decreased from 24 to 15 days. Then, the modified ASW was used for the fermentation of A. terreus strain PF26 in a 500 l stirred bioreactor, consequently 2·5 g l(-1) of (+)-terrein production was achieved.

SIGNIFICANCE AND IMPACT OF THE STUDY

The fermentation of marine micro-organisms always needs to use sea water or artificial sea water (ASW), which limits the fermentation on a large scale, as the high-salinity medium may cause the corrosion risk of bioreactor. In this study, the ASW formula is simplified to reduce the sea water salinity and improve the yield of (+)-terrein, finally, the modified ASW was successfully used for the mass production of (+)-terrein by A. terreus strain PF26 in a 500 l bioreactor.

Transgenic labeling of parvalbumin-expressing neurons with tdTomato

Parvalbumin (PVALB)-expressing fast-spiking interneurons subserve important roles in many brain regions by modulating circuit function and dysfunction of these neurons is strongly implicated in neuropsychiatric disorders including schizophrenia and autism. To facilitate the study of PVALB neuron function we need to be able to identify PVALB neurons in vivo. We have generated a bacterial artificial chromosome (BAC) transgenic mouse line expressing the red fluorophore tdTomato under the control of endogenous regulatory elements of the Pvalb gene locus (JAX # 027395). We show that the tdTomato transgene is faithfully expressed relative to endogenous PVALB expression throughout the brain. Furthermore, targeted patch clamp recordings confirm that the labeled populations in neocortex, striatum, and hippocampus are fast-spiking interneurons based on intrinsic properties. This new transgenic mouse line provides a useful tool to study PVALB neuron function in the normal brain as well as in mouse models of psychiatric disease.

Brains, genes, and primates

One of the great strengths of the mouse model is the wide array of genetic tools that have been developed. Striking examples include methods for directed modification of the genome, and for regulated expression or inactivation of genes. Within neuroscience, it is now routine to express reporter genes, neuronal activity indicators, and opsins in specific neuronal types in the mouse. However, there are considerable anatomical, physiological, cognitive, and behavioral differences between the mouse and the human that, in some areas of inquiry, limit the degree to which insights derived from the mouse can be applied to understanding human neurobiology. Several recent advances have now brought into reach the goal of applying these tools to understanding the primate brain. Here we describe these advances, consider their potential to advance our understanding of the human brain and brain disorders, discuss bioethical considerations, and describe what will be needed to move forward.

The accuracy of circulating microRNA-21 in the diagnosis of colorectal cancer: a systematic review and meta-analysis

AIM

The accuracy and clinical value of circulating microRNA-21 (miR-21) were assessed as a novel diagnostic biomarker of colorectal cancer (CRC).

METHOD

Medline/PubMed, EMBASE, the Cochrane Library databases and grey literature (Google scholar; British Library) were searched up to 29 September 2014 for eligible studies of the association between blood-based miR-21 and a diagnosis of CRC. Quality Assessment of Diagnostic Accuracy Studies (QUADAS) was employed to assess the quality of the included studies by two investigators. Stata12.0 and Meta-DiSc1.4 software were applied to test the heterogeneity using Cochran's Q test and I(2) statistics and to perform the meta-analysis.

RESULTS

Seven studies with 676 CRC patients and 417 controls were included in the meta-analysis. All were of high quality (QUADAS scores 12 or 13). For miR-21, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio to predict CRC were 75% [95% confidence interval (CI) 63-83%], 84% (95% CI 79-87%), 4.61 (95% CI 3.38-6.29), 0.30 (95% CI 0.20-0.46) and 16.89 (95% CI 7.56-37.73) after using a random-effects model analysis. The area under the summary receiver operating characteristic curve was 0.86 (95% CI 0.83-0.89).

CONCLUSION

The results suggest that circulating miR-21 is a biomarker with moderate sensitivity and specificity for CRC.

Composting and gypsum amendment of broiler litter to reduce nutrient leaching loss

The effect of composted litter relative to fresh litter on leaching losses of nutrients has not been well documented. Fresh and composted broiler litter was surface-applied to bermudagrass (hay) [ (L.) Pers.] established in undisturbed soil columns based on N need of the grass in the presence or absence of flue gas desulfurization (FGD) gypsum to evaluate an approach to reduce broiler litter nutrient leaching potential. Columns were periodically leached and biomass was harvested during the 60-d experiment. Total N applied to bermudagrass from broiler litter was 320 kg ha. Gypsum was mixed with fresh and composted litter at the rate based on 20% of litter weight. For composted broiler litter, NO-N, P, K, Cu, and Zn contents in the leachate obtained from the first leaching event were 58, 50, 40, 32, and 38% less than fresh broiler litter, respectively. Significant decreases in NO-N (13%), P (53%), Cu (17%), and Zn (28%) in leachate were obtained when gypsum was mixed with fresh broiler litter. Fresh broiler litter and composted broiler litter applications increased bermudagrass growth compared with the control and gypsum significantly increased yields when mixed with broiler litter. Composted broiler litter application significantly increased N and organic C in the soil compared with fresh litter. Results demonstrate that coapplication of composted broiler litter with FGD gypsum provide the most effective management option for minimizing leaching losses of nutrients while sustaining crop productivity.

Evaluation of effectiveness of hydrocolloid dressing vs ceramide containing dressing against pressure ulcers

OBJECTIVE

Pressure Ulcers (PUs) often is an indication of quality of nursing care as it remains as severe manifestation of the integrity of impaired skin. Our study designed to evaluate the effectiveness of hydrocolloid dressings and ceramide dressings in healing of PU.

PATIENTS AND METHODS

The study was done at Chinese hospital between Feb 2014-November 2014. 72 study group patients and 25 control group patients were included in the study. The study group patients were divided into Group A with 24 patients received only ordinary hydrocolloid dressings, Group B with 24 patients who ceramide containing hydrocolloid dressings and Group C with 24 patients received both hydrocolloid and ceramide dressings. Dressings were applied for 4 weeks. The dressings were changed every 10 days and skin conditions such as pH of the skin, hydration are measured by capacitive method.

RESULTS

Among 72 study population 48 (66.7%) were male and 24 (33.3%) were females. Group A with 18 (75%) males and 6 (25%) females, group B with 20 (83.3%) males and 4 (16.7%) females, and group C with 10 (41.7%) males and 14 (58.3%) females. 25 Control group patients with 8 (32%) males and 16 (68%) females. Erythema seen in 4/24 (16.67%) group A patients, group B and C patients had 1/24 (4.17%) erythema. In control group patients 6/25(24%) developed erythema.

CONCLUSIONS

In our study, we evaluated the effectiveness of the hydrocolloid dressings and ceramide containing dressings in which ceramide containing dressings showed effective prevention and water holding capacity. Our study highlights that ceramide containing dressings found to be more effective in reducing erythema and improving the healing of PU.

Esterase in imported fire ants, Solenopsis invicta and S. richteri (Hymenoptera: Formicidae): activity, kinetics and variation

Solenopsis invicta and Solenopsis richteri are two closely related invasive ants native to South America. Despite their similarity in biology and behavior, S. invicta is a more successful invasive species. Toxic tolerance has been found to be important to the success of some invasive species. Esterases play a crucial role in toxic tolerance of insects. Hence, we hypothesized that the more invasive S. invicta would have a higher esterase activity than S. richteri. Esterase activities were measured for workers and male and female alates of both ant species using α-naphthyl acetate and β-naphthyl acetate as substrates. Esterase activities in S. invicta were always significantly higher than those in S. richteri supporting our hypothesis. In S. invicta, male alates had the highest esterase activities followed by workers then female alates for both substrates. In S. richetri, for α-naphthyl acetate, male alates had the highest activity followed by female alates then workers, while for β-naphthyl acetate, female alates had the highest activity followed by male alates then workers. For workers, S. richteri showed significantly higher levels of variation about the mean esterase activity than S. invicta. However, S. invicta showed significantly higher levels of variation in both female and male alates.

CRISPR-Cas9 knockin mice for genome editing and cancer modeling

CRISPR-Cas9 is a versatile genome editing technology for studying the functions of genetic elements. To broadly enable the application of Cas9 in vivo, we established a Cre-dependent Cas9 knockin mouse. We demonstrated in vivo as well as ex vivo genome editing using adeno-associated virus (AAV)-, lentivirus-, or particle-mediated delivery of guide RNA in neurons, immune cells, and endothelial cells. Using these mice, we simultaneously modeled the dynamics of KRAS, p53, and LKB1, the top three significantly mutated genes in lung adenocarcinoma. Delivery of a single AAV vector in the lung generated loss-of-function mutations in p53 and Lkb1, as well as homology-directed repair-mediated Kras(G12D) mutations, leading to macroscopic tumors of adenocarcinoma pathology. Together, these results suggest that Cas9 mice empower a wide range of biological and disease modeling applications.

Striatal circuits, habits, and implications for obsessive-compulsive disorder

Increasing evidence implicates abnormalities in corticostriatal circuits in the pathophysiology of obsessive-compulsive disorder (OCD) and OC-spectrum disorders. Parallels between the emergence of repetitive, compulsive behaviors and the acquisition of automated behaviors suggest that the expression of compulsions could in part involve loss of control of such habitual behaviors. The view that striatal circuit dysfunction is involved in OC-spectrum disorders is strengthened by imaging and other evidence in humans, by discovery of genes related to OCD syndromes, and by functional studies in animal models of these disorders. We highlight this growing concordance of work in genetics and neurobiology suggesting that frontostriatal circuits, and their links with basal ganglia, thalamus and brainstem, are promising candidates for therapeutic intervention in OCD.

Contribution of infection and peripheral artery disease to severity of diabetic foot ulcers in Chinese patients

AIM

The objective of the current ongoing study was to evaluate the characteristics of diabetic patients with newly diagnosed foot ulcer in Burn & Plastic Hospital of PLA General Hospital.

METHODS

A total of 1002 consecutive patients presenting with a new foot ulcer between March 2007 and September 2013 were enrolled. All enrolled patients were classified based on presence or absence of collateral infection, disabling comorbidities and peripheral arterial disease (PAD).

RESULTS

Of patients, 70.05% had PAD, which occurred significantly more in elderly adults. Patients with PAD had higher incidence of infection (58.9% vs. 41.5% in non-PAD group) and disabling comorbidities (79% in PAD and 61% in non-PAD; p < 0.038). There was no significant difference observed in depth, size and duration of foot ulcers between the PAD and non-PAD group of enrolled diabetic patients.

CONCLUSIONS

Diabetic foot ulcer is more prominent in patients with PAD that is further reflected by significantly more underlying cases of infection and disabling comorbidity.

Sensory integration in mouse insular cortex reflects GABA circuit maturation

Insular cortex (IC) contributes to a variety of complex brain functions, such as communication, social behavior, and self-awareness through the integration of sensory, emotional, and cognitive content. How the IC acquires its integrative properties remains unexplored. We compared the emergence of multisensory integration (MSI) in the IC of behaviorally distinct mouse strains. While adult C57BL/6 mice exhibited robust MSI, this capacity was impaired in the inbred BTBR T+tf/J mouse model of idiopathic autism. The deficit reflected weakened γ-aminobutyric acid (GABA) circuits and compromised postnatal pruning of cross-modal input. Transient pharmacological enhancement by diazepam in BTBR mice during an early sensitive period rescued inhibition and integration in the adult IC. Moreover, impaired MSI was common across three other monogenic models (GAD65, Shank3, and Mecp2 knockout mice) displaying behavioral phenotypes and parvalbumin-circuit abnormalities. Our findings offer developmental insight into a key neural circuit relevant to neuropsychiatric conditions like schizophrenia and autism.

Enhancing multimodality functional and molecular imaging using glucose-coated gold nanoparticles

AIM

To describe how pegylated glucose-coated gold nanoparticles (PEG-Glu-GNPs) can help improve computed tomography (CT) imaging.

MATERIALS AND METHODS

PEG-Glu-GNPs were designed for use as an imaging nanoprobe to act an effective contrast agent for both CT and PET scans. Twelve BALB/c mice were divided into two groups: mice with injected with PEG-Glu-GNPs and control mice. The mice were examined using high-resolution micro-CT at different time intervals (24 h, 7 days, and 15 days) after the injection of the particles. Greyscale density and CT attenuation values were determined to trace the excretion of the particles over time.

RESULTS

Tumour contours were easily distinguished from surrounding tissue in mice injected with PEG-Glu-GNPs but not controls. This distinction was still visible at 7 days, but not at 15 days post-injection.

CONCLUSION

Molecular imaging technology has enabled the development of a new generation of imaging probes. These sophisticated probes can visualize biological processes or enable early diagnosis of diseases in vivo. Compared to conventional CT images and PET scans, PEG-Glu-GNPs significantly improved image quality at the cellular and molecular level, which can significantly aid the early detection of cancer or cancer metastases.

ERβ- and prostaglandin E2-regulated pathways integrate cell proliferation via Ras-like and estrogen-regulated growth inhibitor in endometriosis

In endometriosis, stromal and epithelial cells from the endometrium form extrauterine lesions and persist in response to estrogen (E2) and prostaglandin E2 (PGE2). Stromal cells produce excessive quantities of estrogen and PGE2 in a feed-forward manner. However, it is unknown how estrogen stimulates cell proliferation and survival for the establishment and persistence of disease. Previous studies suggest that estrogen receptor-β (ERβ) is strikingly overexpressed in endometriotic stromal cells. Thus, we integrated genome-wide ERβ binding data from previously published studies in breast cells and gene expression profiles in human endometriosis and endometrial tissues (total sample number = 81) and identified Ras-like, estrogen-regulated, growth inhibitor (RERG) as an ERβ target. Estradiol potently induced RERG mRNA and protein levels in primary endometriotic stromal cells. Chromatin immunoprecipitation demonstrated E2-induced enrichment of ERβ at the RERG promoter region. PGE2 via protein kinase A phosphorylated RERG and enhanced the nuclear translocation of RERG. RERG induced the proliferation of primary endometriotic cells. Overall, we demonstrated that E2/ERβ and PGE2 integrate at RERG, leading to increased endometriotic cell proliferation and represents a novel candidate for therapeutic intervention.

Effects of cryopreservation on motility characteristics and enzyme activity of sperm in a Chinese fish Nibea albiflora

BACKGROUND

Growing evidence suggests that among the causes which deteriorate qualitative and functional characteristics of sperm after freezing and thawing, there are those linked to decrease of sperm motility and release of various enzymes in the cells and seminal plasma.

OBJECTIVE

In the present study, the motility, fertilization and enzyme activity of sperm were analyzed after cryopreservation.

MATERIALS AND METHODS

Computer-assisted sperm motility analysis (CASA) was used to evaluate the effect of cryopreservation on sperm motility of Nibea albiflora.

RESULTS

The activities of total adenosine triphosphatase (ATPase), creatine kinase (CK), succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GR) in fresh and frozen seminal plasma and spermatozoa were measured respectively. Cryopreservation led to a decline in the percentage of motile sperm, moreover, other parameters of sperm motion, curvilinear and straight line velocities, linearity were changed observably (p < 0.05), the fertilizing capacity of post-thaw sperm was lower than that of the fresh sperm significantly. After cryopreservation, the activities of total ATPase, CK, SDH, LDH, SOD, CAT and GSH-Px increased in seminal plasma and decreased in spermatozoa respectively, but GR activity varied contrarily, GR activity dropped in seminal plasma and increased in spermatozoa.

CONCLUSION

Cryopreservation had significant effects on the motility characteristics, fertilization ability and enzyme activity of the sperm of Nibea albiflora.

Bactericidal thurincin H causes unique morphological changes in Bacillus cereus F4552 without affecting membrane permeability

Thurincin H is an antilisterial bacteriocin produced by Bacillus thuringiensis SF361. It exhibits inhibitory activity against a wide range of Gram-positive foodborne pathogens and spoilage bacteria including Listeria monocytogenes, B. cereus, and B. subtilis. This hydrophobic, anionic bacteriocin folds into a hairpin structure maintained by four pairs of unique sulfur to α-carbon thioether bonds. As its hydrophobicity and structure are quite different from most archived bacteriocins, this study aimed to elucidate its mode of action and compare it with the mechanisms of other well-characterized bacteriocins. The results indicated that, although bactericidal to B. cereus F4552, thurincin H did not lead to optical density reduction or detectable changes in cell membrane permeability. B. cereus F4552 imaged by scanning electron microscopy after treatment with thurincin H at 32 × MIC showed regular rod-shaped cells, while only cells treated with thurincin H at the elevated levels of 256 × MIC showed loss of cell integrity and rigidity. Both concentrations caused greater than 99% of cell viability reduction. In contrast, nisin caused significant cell membrane permeability at concentration as low as 2 × MIC. These results indicated a difference in the mode of action for thurincin H compared with the generalized pore-forming mechanism of many lantibiotics, such as nisin.

Optogenetic mapping of cerebellar inhibitory circuitry reveals spatially biased coordination of interneurons via electrical synapses

We used high-speed optogenetic mapping technology to examine the spatial organization of local inhibitory circuits formed by cerebellar interneurons. Transgenic mice expressing channelrhodopsin-2 exclusively in molecular layer interneurons allowed us to focally photostimulate these neurons, while measuring resulting responses in postsynaptic Purkinje cells. This approach revealed that interneurons converge upon Purkinje cells over a broad area and that at least seven interneurons form functional synapses with a single Purkinje cell. The number of converging interneurons was reduced by treatment with gap junction blockers, revealing that electrical synapses between interneurons contribute substantially to the spatial convergence. Remarkably, gap junction blockers affected convergence in sagittal slices, but not in coronal slices, indicating a sagittal bias in electrical coupling between interneurons. We conclude that electrical synapse networks spatially coordinate interneurons in the cerebellum and may also serve this function in other brain regions.